Methods of manufacturing a semiconductor device and a semiconductor memory device thereby

ABSTRACT

A method of manufacturing a semiconductor device comprises forming memory cells on a memory cell region, alternately forming a sacrificial layer and an insulating interlayer on a connection region for providing wirings configured to electrically connect the memory cells, forming an etching mask pattern including etching mask pattern elements on a top sacrificial layer, forming blocking sidewalls on either sidewalls of each of the etching mask pattern element, forming a first photoresist pattern selectively exposing a first blocking sidewall furthermost from the memory cell region and covering the other blocking sidewalls, etching the exposed top sacrificial layer and an insulating interlayer to expose a second sacrificial layer, forming a second photoresist pattern by laterally removing the first photoresist pattern to the extent that a second blocking sidewall is exposed, and etching the exposed top and second sacrificial layers and the insulating interlayers to form a staircase shaped side edge portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 USC §119 to Korean PatentApplication No. 10-2011-0005728, filed on Jan. 20, 2011 in the KoreanIntellectual Property Office (KIPO), the contents of which are hereinincorporated by reference in their entirety.

TECHNICAL FIELD

The inventive concept described herein relates to methods ofmanufacturing a semiconductor device and a semiconductor memory devicethereby. The inventive concept, in particular, relates to methods offorming a vertically integrated connecting structure by trimming aphotoresist layer uniformly, methods of manufacturing a semiconductordevice using the same, and a semiconductor memory device thereby.

DESCRIPTION OF THE RELATED ART

Recent demand for highly integrated semiconductor memory devices havecalled for vertical type semiconductors. Vertical type semiconductordevices have a number of thin film layers that are verticallyintegrated. Corresponding photolithography process steps to form thevertical layers can be complex, adding to manufacturing costs.Therefore, a need exists for simplified manufacturing processes forreducing the number of photolithography process steps and devicestructures.

SUMMARY

In an embodiment of the present inventive concept, a method ofmanufacturing a semiconductor device comprises a step of forming aplurality of memory cells on a memory cell region in a substrate, a stepof alternately forming a sacrificial layer and an insulating interlayeron a connection region for providing a plurality of wirings configuredto electrically connect the plurality of memory cells, a step of formingan etching mask pattern including a plurality of etching mask patternelements on a top sacrificial layer, a step of forming blockingsidewalls on either sidewalls of each of the etching mask patternelement, a step of forming a first photoresist pattern selectivelyexposing a first blocking sidewall furthermost from the memory cellregion and covering the other blocking sidewalls, the first photoresistpattern exposing a predetermined portion of the top sacrificial layer, astep of etching the exposed top sacrificial layer and an insulatinginterlayer below the exposed top sacrificial layer to expose a secondsacrificial layer, a step of forming a second photoresist pattern bylaterally removing the first photoresist pattern to the extent that asecond blocking sidewall is exposed, the second photoresist exposing thepredetermined portion of the top sacrificial layer, and a step ofetching the exposed top and second sacrificial layers and the insulatinginterlayers below the respective top and second sacrificial layers usingthe second photoresist pattern to form a staircase shaped side edgeportion.

In a further embodiment of the present inventive concept, the etchingmask pattern is formed using amorphous carbon or photoresist. Theetching mask pattern elements have a first width, and a gap betweenadjacent etching mask pattern elements having blocking sidewall hassubstantially the same width with the first width. Width of the etchingmask pattern and the sidewall blocking pattern combined is substantiallythe same with width of an exposed portion of the sacrificial layerpattern at the side edge portion of the connecting structure. The numberof the etching mask pattern elements is greater than the number ofsacrificial layers formed by the step of alternately forming asacrificial layer and an insulation interlayer. The blocking sidewallsare formed using a material having an etching selectivity with respectto the sacrificial layer, the etching mask pattern and the firstphotoresist pattern, respectively.

In a further embodiment of the present inventive concept, the method ofmanufacturing a semiconductor device further comprises a step ofremoving the first exposed blocking sidewall before the step of etchingthe exposed top sacrificial layer, and a step of removing the secondexposed blocking sidewall before the step of etching the exposed top andsecond sacrificial layers.

In a further embodiment of the present inventive concept, the method ofmanufacturing a semiconductor device further comprises a step of forminga polymer layer on an upper surface portion of the first photoresistpattern before the step of forming a second photoresist pattern.

In another embodiment of the present inventive concept, a method ofmanufacturing a semiconductor device comprises a step of forming Nsacrificial layers on a memory cell region and a connection region in asubstrate, a step of forming N−1 insulation interlayers between the Nsacrificial layers, a step of forming an etching mask pattern includingN/2 etching mask pattern elements over the connection region, a step offorming sidewall blocking on either sidewalls of the etching maskpattern elements, a step of forming a photoresist layer over the etchingmask pattern elements, a step of trimming the photoresist over theconnection region to expose a furthermost sidewall blocking from thememory cell region and a predetermined portion of the top sacrificiallayer, a step of etching the exposed top sacrificial layer and a topinsulating interlayer below the top sacrificial layer to expose a secondsacrificial layer below the top insulating interlayer, and a step ofrepeating the steps of trimming and etching the exposed top sacrificiallayer until a bottom sacrificial layer is exposed to form a staircaseshaped edge portion in the connection region.

In a further embodiment of the present inventive concept, thesacrificial layer is formed using silicon nitride and the insulatinginterlayer is formed using silicon oxide. The staircase shaped edgeportion includes the bottom sacrificial layer and N−1 steps on thebottom sacrificial layer, each step having uniform width and height.

In a further embodiment of the present inventive concept, a method ofmanufacturing a semiconductor device further comprises a step of formingan insulating layer after the step of repeating, and a step of forming Ncontact plugs through the insulating layer over the connection region toexpose the sacrificial layers of the staircase shaped edge portion.

In a further embodiment of the present inventive concept, a method ofmanufacturing a semiconductor device further comprises a step of forminga plurality of channel holes through the sacrificial and insulatinglayers over the cell formation region, the channel holes exposing thesubstrate, a step of forming a channel layer in the channel holes, and astep of forming a bit line structure making an electric contact with anupper surface portion of the channel layer pattern. The channel layerincludes a tunnel insulating layer, a charge storing layer and ablocking dielectric layer on an inner surface portion of the channelholes.

In a further embodiment of the present inventive concept, a method ofmanufacturing a semiconductor device further comprises a step ofremoving the outermost sidewall blocking before the step of etching theexposed top sacrificial layer.

In another embodiment of the present inventive concept, a semiconductormemory device comprises a memory cell region having a plurality ofvertical memory cells, a memory connection region having a plurality ofcontact plugs configured to electrically connect the plurality of memorycells, a plurality of alternate layers of a conductive layer and aninsulating layer running from the memory cell region to the memoryconnection region, the alternate layers being configured to electricallyconnect the memory cells and contact plugs, and the alternate layershaving a staircase shaped edge portion on the memory connection region,and a polish stopping layer aligned with a top conductive layer of thealternate layers.

In a further embodiment of the present inventive concept, thesemiconductor device further comprises an insulation layer between thepolish stopping layer and the top conductive layer, the insulation layerhaving larger thickness than each of the insulation interlayers. Thestaircase shaped edge portion includes a plurality of steps on thebottom conductive layer, each step having uniform width and height. Theplurality of steps has top surfaces having the uniform width, the topsurfaces being connected to the corresponding contact plugs.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings.

FIGS. 1 to 8F represent non-limiting, exemplary embodiments as describedherein.

FIG. 1 is a plan view illustrating an arrangement of cell regions in amemory device in accordance with exemplary embodiments.

FIGS. 2A to 2C are plan views illustrating an arrangement of cell blocksand connecting regions in the cell region illustrated in FIG. 1.

FIG. 3A is a perspective view illustrating a connecting structure inaccordance with exemplary embodiments.

FIG. 3B is a cross-sectional view illustrating a connecting region inthe connecting structure illustrated in FIG. 3A.

FIGS. 4A to 4O are cross-sectional views for explaining a method ofmanufacturing the connecting structure illustrated in FIGS. 1 & 2 inaccordance with exemplary embodiments.

FIGS. 5A to 5F are plan views of an etching mask used for performingeach etching step for forming a connecting structure in accordance withexemplary embodiments.

FIG. 6 is a plan view for explaining a trimming process of a photoresistpattern.

FIGS. 7A to 7D are cross-sectional views for explaining a method ofmanufacturing a connecting structure illustrated in FIGS. 1 & 2 inaccordance with another exemplary embodiments.

FIGS. 8A to 8F are cross-sectional views illustrating a method ofmanufacturing a vertical type semiconductor device in accordance withexemplary embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments will be described more fully hereinafterwith reference to the accompanying drawings, in which some exemplaryembodiments are shown. The present inventive concept may, however, beembodied in many different forms and should not be construed as limitedto the exemplary embodiments set forth herein. Rather, these exemplaryembodiments are provided so that this description will be thorough andcomplete, and will fully convey the scope of the present inventiveconcept to those skilled in the art. In the drawings, the sizes andrelative sizes of layers and regions may be exaggerated for clarity.

It will be understood that when an element or layer is referred to asbeing “on,” “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element or layeror intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. Like numerals refer to likeelements throughout. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section discussed below could be termed asecond element, component, region, layer or section without departingfrom the teachings of the present inventive concept.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularexemplary embodiments only and is not intended to be limiting of thepresent inventive concept. As used herein, the singular forms “a,” “an”and “the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. It will be further understood thatthe terms “comprises” and/or “comprising,” when used in thisspecification, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Exemplary embodiments are described herein with reference tocross-sectional illustrations that are schematic illustrations ofidealized exemplary embodiments (and intermediate structures). As such,variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, exemplary embodiments should not be construed as limitedto the particular shapes of regions illustrated herein but are toinclude deviations in shapes that result, for example, frommanufacturing. The regions illustrated in the figures are schematic innature and their shapes are not intended to illustrate the actual shapeof a region of a device and are not intended to limit the scope of thepresent inventive concept.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this inventive concept belongs. Itwill be further understood that terms, such as those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Hereinafter, exemplary embodiments on methods of forming a connectingstructure and methods of manufacturing a semiconductor device using thesame will be explained in detail.

FIG. 1 is a plan view illustrating an arrangement of cell regions in amemory device in accordance with exemplary embodiments. FIGS. 2A to 2Care plan views illustrating an arrangement of cell blocks and connectingregions in the cell region illustrated in FIG. 1.

Referring to FIG. 1, a memory device may include a cell array region CARincluding arranged memory cells and a peripheral circuit region PERincluding circuits for driving the memory cells.

The cell array region CAR may include cell blocks CBL having a pluralitymemory cells and a connecting region CR. The connecting region CR may beformed with various positional relationship with the cell block CBL. Theconnecting region CR may include wiring structures connected toconductive lines included in the memory cells.

Referring to FIGS. 2A to 2C, the connecting region CR may have variouspositional relationship with the cell block CBL. Particularly, FIG. 2Ashows that the connecting region CR may be provided at one sidewall ofthe cell block CBL. FIG. 2B shows that the connecting region CR may beprovided at both facing sidewalls of the cell block CBL. FIG. 2C showsthat connecting region CR may be provided at all the sidewalls of thecell block CBL.

Memory cells formed in the cell block CBL may be integrated in avertical direction. Conductive patterns vertically integrated may beextended from the memory cells in a horizontal direction to theconnecting region for electrical connections. The extended portions ofthe conductive patterns may be formed so as to make a connection withtheir corresponding contact plugs in the connecting region.

To form the wirings having the above-described shape, a connectingstructure formed from the cell block CBL to the connecting region CR maybe required. The connecting structure may be a mold pattern for formingthe vertically integrated wirings. Alternatively, the connectingstructure may be a vertically integrated wiring itself.

FIG. 3A is a perspective view illustrating a connecting structure inaccordance with exemplary embodiments. FIG. 3B is a cross-sectional viewillustrating a connecting region in the connecting structure illustratedin FIG. 3A.

Referring to FIGS. 3A & 3B, a substrate 10 includes a cell block regionCBL and a connecting region CR. The cell block region CBL may beprovided for forming cells and the connecting region CR may be providedadjacent to the cell block region CBL and include patterns for making anelectric connection of the cells.

A connecting structure 55 may extend from the cell block region CBL tothe connecting region CR. The connecting region CR may be provided atleast one sidewall of the cell block region CBL with a distance. Theconnecting region CR may be provided adjacent to four sidewalls of thecell block region CBL.

The connecting structure 55 may include an integrated shape ofsacrificial layer pattern 31 including first, second, third, fourth,fifth, sixth, seventh and eighth sacrificial layer patterns 31 a˜31 hand insulating interlayer pattern 21 including alternately andrepeatedly formed first, second, third, fourth, fifth, sixth and seventhinsulating interlayer patterns 21 a˜21 g.

The sacrificial layer pattern 31 and the insulating interlayer pattern21 may include material having different etching selectivity from eachother. Particularly, the sacrificial layer pattern 31 may be formedusing silicon nitride or polysilicon. The insulating interlayer pattern21 may be formed using silicon oxide. When the sacrificial layer pattern31 is formed using an insulating silicon nitride, the whole connectingstructure 55 may be formed using an insulating material. In this case,the connecting structure 55 may be provided as a mold pattern forforming integrated wirings. When the sacrificial layer 31 is formedusing polysilicon, the sacrificial layer pattern 31 may have conductiveproperty. Accordingly, the connecting structure 55 may be provided asthe wirings.

In the connecting structure 55, the sacrificial layer pattern 31 and theinsulating interlayer pattern 21 positioned at the connecting region CRmay have a side edge portion of a staircase shape. That is, anunderlying sacrificial layer pattern may have a wider area than an upperpositioned sacrificial layer pattern.

Since the side edge portion of the sacrificial layer pattern 31 may havethe staircase shape, a portion of an upper surface portion of theunderlying sacrificial layer pattern may be exposed by a differencebetween pattern widths of the underlying sacrificial layer pattern andthe upper positioned sacrificial layer pattern. The exposed uppersurface portion of each sacrificial layer pattern 31 may be used as apad for making a connection with a contact plug. Width deviation of theexposed upper surface from a preset value may cause the contact plug toform out of a desired position.

In exemplary embodiments, the widths of the exposed upper surfaceportions of the sacrificial layer patterns 31 at each layer may generatelittle difference and a process variation from the preset value may belittle. Particularly, the width of the exposed upper surface portion maybe less than about 100 Å.

FIGS. 4A to 4O are cross-sectional views for explaining a method ofmanufacturing the connecting structure illustrated in FIGS. 1 & 2 inaccordance with exemplary embodiments. FIGS. 4A to 4O arecross-sectional views of the connecting structure provided in aconnecting region. FIGS. 4A to 4O are cross-sectional views cut along aline I-I′ in FIG. 5A.

FIGS. 5A to 5F are plan views of an etching mask used for performingeach etching step for forming a connecting structure in accordance withexemplary embodiments. FIG. 6 is a plan view for explaining a trimmingprocess of a photoresist pattern.

Referring to FIGS. 4A & 5A, a pad insulating layer 12 may be formed on asubstrate 10 including a cell block region and a connecting region.

On the pad insulating layer 12, a sacrificial layer 30 including afirst, second, third, fourth, fifth, sixth, seventh and eighthsacrificial layers 30 a˜30 h and an insulating layer 20 including first,second, third, fourth, fifth, sixth and seventh insulating layers 20a˜20 g may be subsequently and repeatedly integrated. At the uppermostlayer, the sacrificial layer may be formed. The insulating layer 20 maybe formed by depositing silicon oxide. The sacrificial layer 30 may beformed using a material having an etching selectivity with respect tothe insulating interlayer 20. Particularly, the sacrificial layer 30 maybe formed using silicon nitride or polysilicon.

The first to eighth sacrificial layers 30 a˜30 h may be formed to havethe same height. In addition, the first to seventh insulatinginterlayers 20 a˜20 g may be formed to have the same height. Inexemplary embodiments, the sacrificial layer 30 may include eight layersand the insulating interlayer 20 may include seven layers. The first toeighth sacrificial layers 30 a˜30 h may be formed on the substrate 10and the first to seventh insulating interlayers 20 a˜20 g may be formedbetween the first to eighth sacrificial layers 30 a˜30 h.

On the uppermost eighth sacrificial layer 30 h, a first mask layer (notillustrated) may be formed. The first mask layer may be formed by a spincoating process. The first mask layer may be formed using a materialthat may be patterned by photolithography. Particularly, the first masklayer may be formed as an amorphous carbon layer, a photoresist layer,etc. In a following process, a buffer layer may be formed on the surfaceportion of the first mask layer and so, the first mask layer may bepreferably formed as the amorphous carbon layer having a hard property.

The first mask layer may be patterned by the photolithography to form anetching mask pattern 40 including first, second, third and fourthetching mask patterns 40 a˜40 d. The etching mask pattern 40 may beformed in the connecting region. In exemplary embodiments, the etchingmask pattern 40 may have a shape surrounding the cell block.

Each of the first to fourth etching mask patterns 40 a, 40 b, 40 c and40 d may have a first width d1. Distance between the first to fourthetching mask patterns 40 a, 40 b, 40 c and 40 d may have a second widthd2. The first width d1 and the second width d2 may be dependent from athird width d3 that may be defined as a width difference between anunderlying sacrificial layer and an upper positioned sacrificial layer.Particularly, a sum of the first and second widths d1 and d2 may betwice of the third width d3 that may be defined as a width differencebetween an underlying sacrificial layer and an upper positionedsacrificial layer. The first width d1 may be smaller than the secondwidth d2. The difference between the first width d1 and the second widthd2 may be in a range from about 10 Å to about 300 Å.

The etching mask pattern 40 may be used as an etching mask forpatterning an edge portion of the first to eighth sacrificial layers 30a˜30 h. Accordingly, the number of the patterns constituting the etchingmask pattern 40 may vary depending on the number of the integratedlayers of the sacrificial layer 30 to be patterned. Particularly, thenumber of the patterns constituting the etching mask pattern 40 may bemore than half of the number of the integrated layers of the sacrificiallayer 30. When the number of the patterns constituting the mask pattern40 is N, 2×N integrated layers of the sacrificial layer 30 may bepatterned.

In order to pattern eight sacrificial layers 30 a˜30 h, four etchingmask patterns 40 a˜40 d may be formed as illustrated in FIG. 4A. Thusformed four etching mask patterns 40 a˜40 d may be defined as the first,second, third and fourth mask patterns 40 a, 40 b, 40 c and 40 d one byone from an edge portion of the connecting region.

Hereinafter, processes of forming the etching mask pattern 40 may beexplained in detail referring to particular numerical values. Thedesignated numerical values including a width of the mask pattern and aninterval between the mask patterns may be illustrated only for theexplanation and may be changed without limitation.

The third width d3 defined as the width difference between theunderlying sacrificial layer and the upper positioned sacrificial layermay be set to about 4,000 Å. That is, a width of an upper surfaceportion of an exposed portion of each layer of the sacrificial layer 30to make a contact with a contact plug may be about 4,000 Å.

The first width d1 of the patterns constituting the etching mask pattern40 for forming the underlying and the upper positioned sacrificiallayers may have a width less than about 4,000 Å by a magnitude of x. Thesecond width d2 between the patterns constituting the etching maskpattern 40 may have a width greater than about 4,000 Å by the magnitudeof x. The magnitude of x may be in a range from about 5 Å to about 150Å. The first width may be about 3,950 Å and the second width d2 may beabout 4,050 Å.

Referring to FIGS. 4B and 5B, a blocking layer 44 may be formed alongthe etching mask pattern 40 and an upper surface portion of the eighthsacrificial layer 30 h. The blocking layer 44 may be formed using amaterial having an etching selectivity with respect to the etching maskpattern 40 and the sacrificial layer 30, respectively. In addition, theblocking layer 44 may be formed using a material having an etchingselectivity with respect to a photoresist pattern to be formed in afollowing process. That is, the blocking layer 44 may be formed using amaterial that may be hardly removed while performing a process ofremoving the etching mask pattern 40. Further, the blocking layer 44 maybe formed using a material that may be hardly removed while performing aprocess of removing the sacrificial layer 30. Particularly, the blockinglayer 44 may be formed using silicon oxide.

A thickness of the blocking layer 44 may be half of a difference betweenthe first width d1 and the second width d2. In this case, a gap betweenthe patterns constituting the etching mask pattern 40 after forming theblocking layer 44 may be the same as the first width d1. Accordingly,the thickness of the blocking layer 44 may be in a range from about 5 Åto about 150 Å. When the first width d1 and the second width d2 are setto 3,950 Å and 4,050 Å as described above, the thickness of the blockinglayer 44 may be about 50 Å. To form the blocking layer 44 having such athin thickness, the blocking layer 44 may be formed by an atomic layerdeposition method.

Referring to FIG. 4C, the blocking layer 44 may be anisotropicallyetched to form sidewall blocking patterns 46 a˜46 g on either sidewallsof the first to fourth etching mask pattern elements 40 a˜40 d of theetching mask pattern 40. Width of one etching mask pattern, e.g. thefirst etching mask pattern 40 a and the sidewall blocking pattern 46 acombined may be width of the sacrificial layer pattern exposed at a sideportion of the connecting structure.

Between the first to seventh sidewall blocking patterns 46 a˜46 g, theeighth sacrificial layer 30 h may be exposed. The sidewall blockingpatterns 46 a˜46 g may be designated as the first, second, third,fourth, fifth, sixth and seventh sidewall blocking patterns 46 a˜46 gone by one from the edge portion of the connecting region.

Referring to FIGS. 4D and 5C, a photoresist layer (not illustrated)covering the eighth sacrificial layer 30 h, the first to fourth etchingmask patterns 40 a˜40 d and the first to seventh sidewall blockingpatterns 46 a˜46 g may be formed. The photoresist layer may be patternedby a photolithography to form a first photoresist pattern 50 a exposinga portion of the first etching mask pattern 40 a among the first tofourth etching mask patterns 40 a˜40 d and the first sidewall blockingpattern 46 a formed at one sidewall of the first etching mask pattern 40a. The first photoresist pattern 50 a may cover a whole region of thecell block CBL and most of the connecting region. The first photoresistpattern 50 a may expose the first sidewall blocking pattern 46 a formedat an edge portion and at one sidewall of the first etching mask pattern40 a.

Referring to FIG. 4E, the exposed portion of the first sidewall blockingpattern 46 a may be selectively removed. The eighth sacrificial layer 30h, the first etching mask pattern 40 a and the first photoresist pattern50 a may not be removed while removing the first sidewall blockingpattern 46 a. When the first sidewall blocking pattern 46 a may besilicon oxide, the first sidewall blocking pattern 46 a may be removedby a dry etching process using an etching gas including SF₆ as a maincomponent.

Referring to FIG. 4F, the eighth sacrificial layer 30 h may be etchedusing the first etching mask pattern 40 a and the first photoresistpattern 50 a as an etching mask. Then, the seventh insulating interlayer20 g may be etched using the seventh sacrificial layer 30 g as an etchstopping layer. After completing the etching process, an edge portion ofthe eighth sacrificial layer 30 h may be etched to form a staircaseshape. In addition, the seventh sacrificial layer 30 g may be exposed bythe third width d3.

Referring to FIGS. 4G, 4H and 6, a portion of the first photoresistpattern 50 a and the first etching mask pattern 40 a may be etched. Thefirst etching mask pattern 40 a and the first photoresist pattern 50 amay be etched by a dry etching process using oxygen or ozone as a mainetching gas. Through the etching process, a sidewall portion of thefirst photoresist pattern 50 a may undergo trimming to form a secondphotoresist pattern 50 b.

The etching process may be stopped when the second sidewall blockingpattern 46 b is exposed. Designated numeral {circle around (1)} may bean etch stopping point in FIG. 6. The etching may be performed until thesecond sidewall blocking pattern 46 b may remain and so, a width of theexposed portion of the eighth sacrificial layer 30 h may be constant.That is, an exposed upper surface portion of the eighth sacrificiallayer 30 h may be the same as a removed portion of the first etchingmask pattern 40 a.

Upper portions of the first photoresist pattern 50 a and the firstetching mask pattern 40 a may be hardly etched while sidewall portionsof the first photoresist pattern 50 a and the first etching mask pattern40 a may be relatively rapidly etched. A polymer layer may be furtherformed on the upper surface portion of the first photoresist pattern 50a before etching the first photoresist pattern 50 a and the firstetching mask pattern 40 a.

Referring to FIG. 4G, with a first polymer layer 55 a, an etching of theupper portion of the first photoresist pattern 50 a may be restrainedwhile performing a following etching process and so, the sidewallportion of the first photoresist pattern 50 a may be etched relativelyrapidly. The first polymer layer 55 a may also be etched while etchingthe first photoresist pattern 50 a and the sidewall of the first etchingmask pattern 40 a to form a second polymer layer (not illustrated).Hereinafter, explanation may be proceeding in case of not including thepolymer layer.

Referring to FIG. 4I, the second sidewall blocking pattern 46 b may beremoved to expose a sidewall of the second etching mask pattern 40 b. Onremoving the second sidewall blocking pattern 46 b, the eighthsacrificial layer 30 h may be exposed by the third width d3. That is,edge portions of the eighth and seventh sacrificial layers 30 h and 30 gmay have a staircase shape while exposing by the third width d3 for eachsacrificial layer.

Referring to FIGS. 4J and 5D, the exposed portions of the eighth andseventh sacrificial layers 30 h and 30 g may be anisotropically etchedusing the second photoresist pattern 50 b as an etching mask. Afterthat, the seventh insulating interlayer 20 g and the sixth insulatinginterlayer 20 f underlying the eighth and seventh sacrificial layers 30h and 30 g, respectively, may be anisotropically etched. Throughperforming the etching process, the edge portions of the eighth andseventh sacrificial layers 30 h and 30 g may be etched to form astaircase shape. In addition, the sixth and seventh sacrificial layersmay be exposed by the preset third width d3.

Referring to FIGS. 4K, 5E and 6, a portion of the second photoresistpattern 50 b may be etched to expose the third sidewall blocking pattern46 c. Designated numeral {circle around (2)} may be an etch stoppingpoint in FIG. 6 while performing the etching process.

Through the etching process, a sidewall of the second photoresistpattern 50 b may undergo trimming to form a third photoresist pattern 50c. The third sidewall blocking pattern 46 c may be removed to expose asidewall of the second etching mask pattern 40 b.

Exposed portions of the sixth to eighth sacrificial layers 30 f˜30 h maybe anisotropically etched using the second etching mask pattern 40 b andthe third photoresist pattern 50 c as an etching mask. Then, the fifthto seventh insulating interlayers 20 e˜20 g, respectively underlying thesixth to eighth sacrificial layers 30 f˜30 h may be anisotropicallyetched. After completing the etching process, the fifth to seventhsacrificial layers 30 e˜30 g may be exposed by the third width d3.

Referring to FIGS. 4L & 6, a portion of the third photoresist pattern 50c and the second etching mask pattern 40 b may be etched to expose thefourth sidewall blocking pattern 46 d. Designated numeral {circle around(3)} may be an etch stopping point in FIG. 6 while performing theetching process.

A sidewall of the third photoresist pattern 50 c may undergo trimmingwhile performing the etching process to form a fourth photoresistpattern 50 d. The fourth sidewall blocking pattern 46 d may be removed.

Exposed portions of the fifth to eighth sacrificial layers 30 e˜30 h maybe anisotropically etched using the fourth photoresist pattern 50 d asan etching mask. Then, the fourth to seventh insulating interlayers 20d˜20 g, respectively underlying the fifth to eighth sacrificial layers30 e˜30 h may be anisotropically etched. After completing the etchingprocess, the fourth to seventh sacrificial layers 30 d˜30 g may beexposed by the third width d3.

Referring to FIGS. 4M & 6, a portion of the fourth photoresist pattern50 d may be etched to expose the fifth sidewall blocking pattern 46 e.Designated numeral {circle around (4)} may be an etch stopping point inFIG. 6 while performing the etching process.

A sidewall of the fourth photoresist pattern 50 d may undergo trimmingwhile performing the etching process to form a fifth photoresist pattern50 e. The fifth sidewall blocking pattern 46 e may be removed.

Exposed portions of the fourth to eighth sacrificial layers 30 d˜30 hmay be anisotropically etched using the fifth photoresist pattern 50 eand the third etching mask pattern 40 c as etching masks. Then, thethird to seventh insulating interlayers 20 c˜20 g, respectivelyunderlying the fourth to eighth sacrificial layers 30 d˜30 h may beanisotropically etched. After completing the etching process, the thirdto seventh sacrificial layers 30 c˜30 g may be exposed by the thirdwidth d3.

Referring to FIGS. 4N & 6, a portion of the fifth photoresist pattern 50e and the third etching mask pattern 40 c may be etched to expose thesixth sidewall blocking pattern 46 f. Designated numeral {circle around(5)} may be an etch stopping point in FIG. 6 while performing theetching process.

Through the etching process, a sixth photoresist pattern 50 f may beformed. The sixth sidewall blocking pattern 46 f may be removed.

Exposed portions of the third to eighth sacrificial layers 30 c˜30 h maybe anisotropically etched using the sixth photoresist pattern 50 f as anetching mask. Then, the second to seventh insulating interlayers 20 b˜20g, respectively underlying the third to eighth sacrificial layers 30c˜30 h may be anisotropically etched. After completing the etchingprocess, the second to seventh sacrificial layers 30 b˜30 g may beexposed by the third width d3.

Referring to FIGS. 4O, 5F and 6, a portion of the sixth photoresistpattern 50 f may be etched to expose the seventh sidewall blockingpattern 46 g. Designated numeral {circle around (6)} may be an etchstopping point in FIG. 6 while performing the etching process.

Through the etching process, a sidewall of the sixth photoresist pattern50 f may undergo trimming to form a seventh photoresist pattern 50 g.The seventh sidewall blocking pattern 46 g may be removed.

Exposed portions of the second to eighth sacrificial layers 30 b˜30 hmay be anisotropically etched using the seventh photoresist pattern 50 gand the fourth etching mask pattern 40 d as etching masks. Then, thefirst to seventh insulating interlayers 20 a˜20 g, respectivelyunderlying the second to eighth sacrificial layers 30 b˜30 h may beanisotropically etched. After completing the etching process, the firstto seventh sacrificial layers 30 a˜30 g may be exposed by the thirdwidth d3.

Then, the seventh photoresist pattern 50 g and the fourth etching maskpattern 40 d may be removed.

Through performing the etching process, a connecting structure 55including the first to eighth sacrificial layer patterns 31 a˜31 h andhaving a staircase shaped edge portion may be completed. The exposedportions at the edge portions of the first to eighth sacrificial layerpatterns 31 a˜31 h may have a constant width of d3. The first to eighthsacrificial layer patterns 31 a˜31 h may be formed by performingphotolithography twice.

The exposed width d3 at the edge portions of the first to eighthsacrificial layer patterns 31 a˜31 h may be the same as a sum of a widthof one pattern among the etching mask patterns and a width of one of thesidewall blocking patterns. Accordingly, the exposed width of the firstto eighth sacrificial layer patterns 31 a˜31 h may have a small processvariation similar to a dispersion degree of a line width of initiallyformed etching mask patterns. Particularly, the exposed width of thefirst to eighth sacrificial layer patterns 31 a˜31 h may have an processvariation less than about 100 Å with respect to a preset value.

FIGS. 7A to 7D are cross-sectional views for explaining a method ofmanufacturing a connecting structure illustrated in FIGS. 1 & 2 inaccordance with another exemplary embodiments.

The same procedure may be performed as explained referring to FIGS. 4Ato 4O except for using the sidewall blocking pattern as an etching maskwhile performing the etching process with respect to each sacrificiallayer.

A structure illustrated in FIG. 4D may be formed through performing thesame procedure explained referring to FIGS. 4A to 4D.

Referring to FIG. 7A, the eighth sacrificial layer 30 h may be etchedusing the first photoresist pattern 60 a, the first etching mask pattern40 a and the first sidewall blocking pattern 46 a as etching masks.Then, the seventh insulating interlayer 20 g may be etched using theseventh sacrificial layer 30 g as an etch stopping layer. Aftercompleting the etching process, an edge portion of the eighthsacrificial layer 30 h may be etched to form a staircase shape. Theseventh sacrificial layer 30 g may be exposed by the selected thirdwidth. The third width may be a sum of a width of one etching maskpattern and a width of one sidewall blocking pattern.

Referring to FIG. 7B, the first sidewall blocking pattern 46 a may beremoved. Then, a portion of the first photoresist pattern 60 a and thefirst etching mask pattern 40 a may be etched to expose the secondsidewall blocking pattern 46 b. Through the etching process, a sidewallof the first photoresist pattern 60 a may undergo trimming to form thesecond photoresist pattern 60 b.

On exposure of the second sidewall blocking pattern 46 b, the etchingmay be stopped. Since the etching may be performed until the secondsidewall blocking pattern 46 b may be exposed, a width of an exposedportion of the eighth sacrificial layer 30 h may be constant. That is,the exposed portion of the eighth sacrificial layer 30 h may be the sameas the removed portions of the first etching mask pattern 40 a and thefirst sidewall blocking pattern 46 a.

The exposed portions of the eighth sacrificial layer 30 h and theseventh sacrificial layer 30 g may be anisotropically etched using thesecond photoresist pattern 60 b and the second sidewall blocking pattern46 b as etching masks. Then, the seventh and sixth insulatinginterlayers 20 f and 20 g, respectively underlying the eighth andseventh sacrificial layers 30 h and 30 g may be anisotropically etched.After completing the etching process, edge portions of the eighth andseventh sacrificial layers 30 h and 30 g may be etched to form astaircase shape and edge portions of the sixth and seventh sacrificiallayers 30 f and 30 g may be exposed by the third width.

Referring to FIG. 7C, the second sidewall blocking pattern 46 b may beremoved. The second photoresist pattern 60 b may be partially etched toexpose the third sidewall blocking pattern 46 c. Through performing theetching process, a sidewall of the second photoresist pattern 60 b mayundergo trimming to form the third photoresist pattern 60 c.

The exposed portions of the sixth and seventh sacrificial layers 30 fand 30 g may be anisotropically etched using the third photoresistpattern 60 c, the second sidewall blocking pattern 46 b and the secondetching mask pattern 40 b as etching masks. Then, the fifth and sixthinsulating interlayers 20 e and 20 f, respectively underlying the sixthand seventh sacrificial layers 30 f and 30 g may be anisotropicallyetched. Through performing the etching process, edge portions of thesixth to eighth sacrificial layers 30 f˜30 h may be etched to form astaircase shape. Edge portions of the fifth to seventh sacrificiallayers 30 e˜30 g may be exposed by the third width.

Then, a portion of the photoresist pattern or the etching mask patternmay be removed to expose the sidewall blocking pattern and thus exposedportion of the sacrificial layer may be etched using the partiallyetched photoresist pattern and the exposed sidewall blocking pattern asetching masks. Processes explained referring to FIGS. 7A and 7B may berepeatedly performed.

After completing the above-described process, first, second, third,fourth, fifth, sixth, seventh and eighth sacrificial layer patterns 31a, 31 b, 31 c, 31 d, 31 e, 31 f, 31 g and 31 h having a staircase shapededge portion may be formed on the substrate 10. Upper edge portion ofeach layer of the sacrificial layer pattern 31 may be exposed by thethird width.

Remaining photoresist pattern 61 and etching mask pattern 40 d may beremoved.

Hereinafter, a method of manufacturing a vertical type semiconductordevice using the above-described method of forming the connectingstructure may be explained. The semiconductor device in an exemplaryembodiment may be a vertical NAND flash memory device. FIGS. 8A to 8Fare cross-sectional views illustrating steps of manufacturing thevertical NAND flash memory device according to the inventive concept.

Referring to FIG. 8A, a plurality of sacrificial layers 102 a˜102 h anda plurality of insulating interlayers 104 a˜104 g are formed on asemiconductor substrate 100. The semiconductor substrate 100 includes acell forming region CELL REGION and a connection region CONNECTINGREGION in a cell array region CAR of FIG. 1. The cell forming regionCELL REGION is a region where memory cells may be formed. The connectionregion CONNECTING REGION is a region where wirings are formed to provideelectrical connections of the memory cells. The semiconductor substrate100 may be a single crystalline substrate and a pad insulating layer(not illustrated) may be formed on the semiconductor substrate 100.

The sacrificial layers 102 a˜102 h and the insulating interlayers 104a˜104 g may be alternately formed. For example, the number of thesacrificial layers 102 a˜102 h is eight, and the number of theinsulating interlayers 104 a˜104 g is seven, for the each of insulatinginterlayers 104 a˜104 g is interposed between two neighboringsacrificial layers. The sacrificial layers 102 a˜102 h may have the samethickness each other. The insulating interlayers 104 a˜104 g may havethe same thickness each other. The sacrificial layers 102 a˜102 h may beformed using a material having an etching selectivity with respect tothe insulating interlayers 104 a˜404 g. For example, the sacrificiallayers 102 a˜102 h may be silicon nitride, and the insulatinginterlayers may be silicon oxide.

On the top sacrificial layer 102 h, an insulating interlayer 106 and apolish stopping layer 108 may be formed for independently processing thecell forming region CELL REGION and the connection region CONNECTINGREGION. The insulating interlayer 106 may cover the top sacrificiallayer 102 h and have a greater thickness that the insulating interlayers104 a˜104 g. The polish stopping layer 108 may be formed using amaterial having a polishing selectivity with respect to silicon oxide.For example, the polish stopping layer 108 may be formed usingpolysilicon or silicon nitride.

Referring to FIG. 8B, the polish stopping layer 108 is patterned tocover the cell forming region CELL REGION and a staircase shaped step isformed in the connection region CONNECTING REGION. The alternate layers102 a˜102 h and 104 a˜104 g which are not covered by the patternedpolish stopping layer 108 a may be patterned to form the staircaseshaped step. The staircase shaped step may be formed in accordance withthe process described referring to FIGS. 4A to 4O. Alternatively, thestaircase shaped step may be formed in accordance with the processdescribed referring to FIGS. 7A to 7D.

After completing the above-described processes using twophotolithography process steps, the staircase shaped step may be formedin the connection region CONNECTING REGION. The each layer of thesacrificial layers 103 a˜103 h may provide a step having a substantiallysame width, having a process variation less than about 100 Å from atargeted width value. The first photolithography process is used forpatterning the polish stopping layer 108, and the secondphotolithography process is used in the processes described in FIG. 4Ato 4O or in FIG. 7A to 7D to form the staircase shaped step.

FIG. 8C shows a planarized insulating layer 128 from an insulating layercovering a resultant structure of FIG. 8B. For example, the insulatinglayer 128 may cover the stopping layer pattern 108 a and the staircaseshaped step having patterned sacrificial layers 103 a˜103 h andinsulation interlayers 105 a˜105 g. The insulating layer may be formedusing silicon oxide. The insulating layer may be planarized to theextent that an upper surface portion of the stopping layer pattern 108 amay be exposed.

FIG. 8C further shows channel holes 120 formed in the cell formingregion CELL REGION. In order to form the channel holes 120, an etchingmask pattern (not illustrated) for defining the channel holes 120 may beformed on the stopping layer pattern 108 a. Using the etching maskpattern, the insulating interlayers 105 a˜105 g, 106 a and the first toeighth sacrificial layer patterns 103 a˜103 h may be subsequently etchedusing the etching mask pattern as an etching mask to form a plurality ofchannel holes 120. The channel holes 120 may arrange in a row.

A first semiconductor material layer (not illustrated) may be formedalong a sidewall of the channel holes 120, a bottom portion of thesubstrate 100, the stopping layer pattern 108 a and the ninth insulatinginterlayer 128. The first semiconductor material layer may be apolysilicon layer. A silicon oxide layer (not illustrated) may be formedon the first semiconductor material layer so as to completely fill upthe inner portion of the channel hole 120.

The silicon oxide layer may be partially etched to form a silicon oxidelayer pattern 124 to the extent that the inner portion of the channelhole 120 may be filled up with silicon oxide. An upper surface portionof the silicon oxide layer pattern 124 may be positioned higher than theeighth sacrificial layer pattern 103 h.

A second semiconductor material layer (not illustrated) filling up theinner portion of the channel hole 120 may be formed on the silicon oxidelayer pattern 124. The second semiconductor material layer may be formedusing the same material as the first semiconductor material layer. Thesecond semiconductor material layer may be polished to expose an uppersurface portion of the stopping layer pattern 108 a. A channel layerpattern 122 having a macaroni shape and a second semiconductor pattern126 may be formed in the channel hole 120.

Referring to FIG. 8D, the stopping layer pattern 108 a and theconnecting structure between the channel layer patterns 122 may beetched to form an opening portion (not illustrated). The opening portionmay have a trench shape extending in one direction. In addition, asurface portion of the substrate 100 may be exposed through a bottomportion of the opening portion.

After forming the opening portion, the first to eighth sacrificial layerpatterns 103 a˜103 h exposed to a sidewall of the opening portion may beremoved to form grooves.

A tunnel insulating layer (not illustrated), a charge trapping layer(not illustrated) and a blocking dielectric layer (not illustrated) maybe formed along the grooves and an inner surface portion of the openingportion. On the blocking dielectric layer, a conductive layer (notillustrated) completely filling up the inner portions of the grooves andthe opening portion may be formed. The conductive layer may be formed bydepositing a conductive material having a good step coveragecharacteristic to restrain a generation of voids. The conductivematerial may include a metal. Particularly, the conductive material mayinclude a material having a low electric resistance such as tungsten,tungsten nitride, titanium, titanium nitride, tantalum, tantalumnitride, platinum, etc. The conductive layer may be formed by forming abarrier metal layer including titanium, titanium nitride, tantalum,tantalum nitride, etc. and then a metal layer including tungsten.

Then, the conductive layer formed in the inner portion of the openingportion may be removed. The removal may be performed through a wetetching process. The conductive layer formed in the inner portion of thegrooves may remain to form first, second, third, fourth, fifth, sixth,seventh and eighth control gate electrodes 110 a, 110 b, 110 c, 110 d,110 e, 110 f, 110 g and 110 h. The first to eighth control gateelectrodes 110 a˜110 h may be called as the first to eighth control gateelectrodes from the substrate 100.

The first to eighth control gate electrodes 110 a˜110 h positioned inthe connecting region may have a staircase shaped side edge portion.Accordingly, the exposed portion of the side edge portion may be used asa pad for connecting a word line. Since the width of each exposedportion at the edge portion of the connecting structure may be constant,the width of the pad portion of the first to eighth control gateelectrodes 110 a˜110 h may be uniform.

Into the substrate 100 at the bottom portion of the opening portionbetween the first to eighth control gate electrodes 110 a˜110 h, n-typeimpurities may be doped to form an impurity doped region (notillustrated) used as a source line (S/L).

An insulating layer filling up the opening portion may be formed and apolishing process may be performed to planarize the insulating layer andto from an insulating layer pattern 130. A tenth insulating layer 132covering the structure including the channel layer pattern 122 and thefirst to eighth control gate electrodes 110 a˜110 h may be formed.

Referring to FIG. 8E, a bit line contact 142 may be formed toelectrically contact with an upper surface portion of the secondsemiconductor pattern 126 through the tenth insulating interlayer 132.Contact plugs 140 a˜140 h contact with the pad portions of the first toeighth control gate electrodes 110 a˜110 h through the tenth insulatinginterlayer 132. Since control gate electrodes 110 a˜110 h may have padportions having uniform width or steps having uniform width, contactdefects due to mis-alignment of pad portions, generated by a deviationof control gate electrodes 110 a˜110 h, may be rarely generated whileforming the first to eighth contact plugs 140 a˜140 h.

Contact plugs 140 a˜140 h and wiring lines 144 may be formed toelectrically contact with the steps having uniform width of the controlgate electrode 110 a˜110 h.

Referring to FIG. 8F, an eleventh insulating interlayer 150 covering thebit line contact 142 and the wiring lines 144 may be formed. Through theeleventh insulating interlayer 150, a contact plug 146 making a contactwith an upper surface portion of the bit line contact 142 and a bit line148 may be formed. The bit line 148 may have a line shape and may makean electric connection with the channel layer pattern 122.

Through the above-described processes, the pad portion of the first toeighth control gate electrodes 110 a˜110 h may have a uniform width andmay be formed at a desired position. In addition, since the connectingstructure may be formed by applying twice of photolithography, the firstto eighth control gate electrodes 110 a˜110 h may be formed with a lowcost.

The vertical type memory device may be manufactured with a low cost inexemplary embodiments.

Although a few exemplary embodiments have been described, those skilledin the art will readily appreciate that many modifications are possiblein the exemplary embodiments without materially departing from the novelteachings and advantages of the present inventive concept. Accordingly,all such modifications are intended to be included within the scope ofthe present inventive concept as defined in the claims. In the claims,means-plus-function clauses are intended to cover the structuresdescribed herein as performing the recited function and not onlystructural equivalents but also equivalent structures. Therefore, it isto be understood that the foregoing is illustrative of various exemplaryembodiments and is not to be construed as limited to the specificexemplary embodiments disclosed, and that modifications to the disclosedexemplary embodiments, as well as other exemplary embodiments, areintended to be included within the scope of the appended claims.

What is claimed is:
 1. A method of manufacturing a semiconductor device comprising steps of: forming a plurality of memory cells on a memory cell region in a substrate; alternately forming a sacrificial layer and an insulating interlayer on a connection region for providing a plurality of wirings configured to electrically connect the plurality of memory cells; forming an etching mask pattern including a plurality of etching mask pattern elements on a top sacrificial layer; forming blocking sidewalls on either sidewalls of each of the etching mask pattern elements; forming a first photoresist pattern selectively exposing a first blocking sidewall furthermost from the memory cell region and covering the other blocking sidewalls, the first photoresist pattern exposing a predetermined portion of the top sacrificial layer; etching the exposed top sacrificial layer and an insulating interlayer below the exposed top sacrificial layer to expose a second sacrificial layer; forming a second photoresist pattern by laterally removing the first photoresist pattern to the extent that a second blocking sidewall is exposed, the second photoresist exposing the predetermined portion of the top sacrificial layer; and etching the exposed top and second sacrificial layers and the insulating interlayers below the respective top and second sacrificial layers using the second photoresist pattern to form a staircase shaped side edge portion.
 2. The method of claim 1, wherein the etching mask pattern is formed using amorphous carbon or photoresist.
 3. The method of claim 1, wherein the etching mask pattern elements have a first width, and a gap between adjacent etching mask pattern elements having blocking sidewall has substantially the same width with the first width.
 4. The method of claim 1, wherein width of the etching mask pattern and the sidewall blocking pattern combined is substantially the same with width of an exposed portion of the sacrificial layer pattern at the side edge portion of the connection region.
 5. The method of claim 1, wherein a number of the etching mask pattern elements is greater than a number of sacrificial layers formed by the step of alternately forming a sacrificial layer and an insulation interlayer.
 6. The method of claim 1, further comprising steps of: removing the first exposed blocking sidewall before the step of etching the exposed top sacrificial layer; and removing the second exposed blocking sidewall before the step of etching the exposed top and second sacrificial layers.
 7. The method of claim 1, further comprising a step of forming a polymer layer on an upper surface portion of the first photoresist pattern before the step of forming a second photoresist pattern.
 8. The method of claim 1, wherein the blocking sidewalls are formed using a material having an etching selectivity with respect to the sacrificial layer, the etching mask pattern and the first photoresist pattern, respectively.
 9. A method of manufacturing a semiconductor device comprising steps of: forming N sacrificial layers on a memory cell region and a connection region in a substrate; forming N−1 insulation interlayers between the N sacrificial layers; forming an etching mask pattern including N/2 etching mask pattern elements over the connection region; forming sidewall blocking on either sidewalls of the etching mask pattern elements; forming a photoresist layer over the etching mask pattern elements; trimming the photoresist over the connection region to expose a furthermost sidewall blocking from the memory cell region and a predetermined portion of a top sacrificial layer; etching the exposed top sacrificial layer and a top insulating layer to expose a second sacrificial layer underlying the top insulating layer; and repeating the steps of trimming and etching the exposed top sacrificial layer until a bottom sacrificial layer is exposed to form a staircase shaped edge portion in the connection region.
 10. The method of claim 9, further comprising steps of: forming an insulating layer after the step of repeating; and forming N contact plugs through the insulating layer over the connection region to expose the sacrificial layers of the staircase shaped edge portion.
 11. The method of claim 9, wherein the sacrificial layer is formed using silicon nitride and the insulating interlayer is formed using silicon oxide.
 12. The method of claim 9, further comprising steps of: forming a plurality of channel holes through the sacrificial and insulating layers over the cell formation region, the channel holes exposing the substrate; and forming a channel layer in the channel holes.
 13. The method of claim 12, further comprising a step of forming a bit line structure making an electric contact with an upper surface portion of the channel layer pattern.
 14. The method of claim 12, wherein the channel layer includes a tunnel insulating layer, a charge storing layer and a blocking dielectric layer on an inner surface portion of the channel holes.
 15. The method of claim 9, further comprising a step of removing the outermost sidewall blocking before the step of etching the exposed top sacrificial layer.
 16. The method of claim 9, wherein the staircase shaped edge portion includes the bottom sacrificial layer and N−1 steps on the bottom sacrificial layer, each step having uniform width and height. 